Typewriter mounting for carriage pinions



June 5, 1951 o. AEBI TYPEWRII'ER MOUNTING FOR CARRIAGE PINIONS AWE/T0 6Orro /75/,

Filed April 8, 1948 Patented June 5, 1951 TYPEWRITER MOUNTING FORCARRIAGE PINION S Otto Aebi, Yverdon, Switzerland, assignor to PaillardS. .A., a corporation of Switzerland Application April 8, 1948, SerialNo. 19,768 In Switzerland April 22, 1947 4 Claims. 1

The present invention relates to a typewriter comprising a carriagesubjected to the action of a spring and having a rack engaging with apinion pivoted in an element secured to the framework of the machine. Inthese typewriters the step by step feed of the carriage during typing isefiected by means of a retaining pawl and a release pawl co-operatingwith one or two ratchet wheels secured rigidly to the shaft of thepinion gearing with the rack of the carriage. Various manufacturers havendeavoured, without much success, to make this escapement devicenoiseless. In fact, for obtaining a satisfactory operation of themachine, it is necessary for the support of the pinion to be securedvery rigidly to the framework of the machine. But the spring acting onthe carriage is generally very strong so as to be capable of rapidlyaccelerating the carriage which in general is of relatively considerableweight. As a result when the accelerated movement of the carriage isstopped by the retaining pawl coming into engagement with one of theteeth of the ratchet wheel, a shock is produced which is distributedthroughout the framework of the typewriter. In view of the violence ofthe shock and as this is repeated with the frequency of typing it willbe seen that for ensuring a satisfactory operation of the machine, it isabsolutely necessary to avoid any movement of the support of the pinion,in other words, it is necessary to provide a very rigid securing of thesupport to the framework. But in order to prevent transmission to theframework of the vibrations resultant upon the shocks and for absorbingthese and reducing the noise, the simplest and most efficacious methodis to provide elements of pliant material so located that there existsno path or metallic connection between the support and the framework, arequirement which appears to exclude the possibility of securing thesupport rigidly to the framework of the typewriter.

The present invention tends to produce a typewriter of the type abovereferred to and of which the support for the pinion is secured rigidlyto the framework whilst avoiding a metallic path between the saidsupport and the framework. For this purpose the machine is provided witha pinion pivoted in a removable support held rigidly in position on theframework by tightening members applying to the said support thrustsdistributed on opposite sides of a plane passing through the axis ofrotation of the pinion and directed at an angle relatively to the saidplane.

A partial view with parts broken away of one form of construction of themachine forming the subject of the invention is shown by way of examplein the accompanying drawing.

According to the accompanying drawing the typewriter is provided with aframework to which are secured the various elements and members of themachine. The framework carries a carriage 2 provided with a platen 3.The carriage slides relatively to the framework of the machine and it issubjected to the action of a spring (not shown) tending to hold the saidcarriage in its extreme left hand position defined by the engagement oftwo stops (not shown) of which one is secured to the framework of themachine and the other to the carriage. The latter also carries a rack lwith which gears a pinion B secured to a shaft 9 rotating in bearings(not shown) provided in a support l2. The shaft 9 also carries anescapement wheel l3 co-operating with a retaining pawl l4 and a releasepawl H5. The pawls I4 and Hi are secured to an arm I! pivoted on thesaid support l2 and are actuated by an actuating member it moved by thekeys of the keyboard during typing.

The support I2 is removable and is secured rigidly to an element 20 ofthe framework by means of a tightening device enabling members ofresilient material to be interposed between the said support l2 and theelement '20 and between the tightening members and the support l2,whilst ensuring a rigid securing of the support on the said element ofthe framework.

The term rigid securing here implies a securing which prevents anymovements of the support i2 having an amplitude which may be deleteriousto the satisfactory operation of the typewriter.

The tightening device is provided with two flaps 2| hinged to theelement 2!! by two spindles 22 parallel to the shaft 9 of the pinion ii.The flaps are connected together at their free ends by a rod 23screw-threaded at its two ends. Nuts 24 and lock-nuts 2t engaging withthese screwthreaded ends, enable the flaps to bear against the support[2. The latter is provided with two bearing surfaces 26 against whichthe flaps 2i bear through the medium of members 2'! of pliant andresilient material. Between the lower surface or bottom surface 28 ofthe support i2 and the element 20 are interposed members 29 of pliantand resilient material.

The operation of the typewriter described is in all respects similar tothat of known machines, but it is to be observed that there is nometallic connection between the support l2 and the framework of themachine. In fact the members 21 and 29 interrupt the mechanicalconnections which may exist between the support 12 and the element 20 onthe one hand and between the support 12 and the tightening members forthe latter on the other hand. By reason of the arrangement adopted inwhich the tightening members apply to the support l2 thrusts which aredistributed on opposite sides of a plane perpendicular to the element 28and passing through the axis of rotation of the pinion 8 on the one handand on the other hand directed obliquely relatively to this plane and inthe direction of the element 28, the securing of the removable supporti2 is very rigid. In particular, no movement of the support [2relatively to the element 20 is to be feared in the direction of theshocks and knocks to which it is subjected during the stopping of theescapement wheel on the retaining pawl. These knocks apply thrusts whichare directed approximately parallel to the movement of the carriage,that'is to say perpendicularly to the axis of the pinion 8. The bearingsurfaces 26 each form an angle with the base surface 28 of the support,so that the ends of the flaps are closer. together than their hingepoints on the element 28. In this manner a movement of the supportperpendicular to the shaft 8 is rendered impossible.

The rod 23 passes through the support through an opening 3ll providedtherein. This opening is of'sufiicient dimensions to avoid anypossibility of contact between this rod and the mass of the support I 2.

On examination of the drawing it will be seen readily that thevibrations'generated in the support during the operation of theescapement cannot be transmitted to the framework, so that the surfaceof the parts in vibration is reduced to the sum of the surfaces of thesupport. As this surface is very small relatively to that of theframework, it is clear that the sound vibrations are practically nolonger transmitted to the air and that the machine is renderednoiseless.

One form of construction of the machine forming the subject of theinvention has been described herein by way of example and with referenceto the drawing but it will be understood that all the elements andmembers described may be replaced directly by their equivalents.However, the machine described has the advantage of being provided witha removable support 12 on which are mounted all the members of theescapement device. The placing in position and withdrawal of theremovable support 12 are very easy and rapid operations. In fact forplacing the support in position, the support being provided with all themembers of the escapement device, it sufiices to place it on theframework, the members 28 being previously placedon the element 28, andthen to lower the two flaps, positioning the rod 23 and tightening andlocking the nuts 24. The support automatically assumes its exactlongitudinal position and no mechanical connections 1. In a typewriter,the combination with a framework and a spring actuated carriage slidableon the framework, of a rack on said carriage, a pinion meshing with saidrack, a support mounting said pinion for rotation, means each pivotallymounted on said framework and each .clampingly engaging one of theopposite sides of said support on one side of a vertical plane passingthrough the axis of said pinion, means of pliant and resilient materialinterposed between said framework and said support, and means forcingthe first means toward one another to clamp the support.

2. The combination according to claim 1, wherein the support includes apair of bearing surfaces one on either side of said plane and each ofthe first means engages one of said bearing REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,459,554 Schweitzer June 19,1923 1,897,699 Hart Feb. 14, 1933 2,138,324 Koca Nov. 29, 1938 2,280,807Dowd et al. Apr. 28, 1942

